Date of Award
Bachelor of Science
Paper Science and Engineering
When coating on a beveled blade coater, the coat weight applied to the base paper is influenced by the doctoring action of the blade. The final coat weight varies as a function of the blade deflection. The blade deflection can be determined by the balance of forces, external and dynamic. The external is the mechanical force applied to the blade, this is also known as the blade loading. The dynamic forces derive from the pressure forces (speed induced), the impulse force (momentum dependent) and finally the hydrodynamic forces. How the roughness of the base sheet affects the blade forces is unknown. By measuring the blade deflection while coating on films with varying roughness, the interaction can be studied under dynamic conditions. Three different films with varying roughness, will be tested under three different blade loading. Experimental measurements of blade deflection will be carried out on a Cylindrical Laboratory Coater, using a position detector mounted on the blade.
There are few conclusions that can be made about the relationship between base sheet roughness and blade deflection. There does not seem to be a correlation between the roughness of the sheet and the deflection of the blade. The reasons for this inconclusive results may be due to the lack inadequate sampling of the amplifier. Because of the problems with the amplifier, the speed of the CLC has to be lowered form 2000 ft/min to 400 ft/min. This lowered speed and lack of needed sensitivity of the amplifier may have introduced error into the results.
Denzer, Derek, "The Effects of Base Sheet Properties on Blade Forces in Beveled Blade Coating" (1997). Paper Engineering Senior Theses. 107.